Cool Approach to Live Fish Transport

A new box for live fish transport that puts fish to sleep with CO2 is showing promising results in Japan.

Bonnie Waycott

A company in Japan has figured out how to sustainably transport large amounts of live fish over long distances. Leasing services firm Nikken Lease Kogyo Co., Ltd's venture into live fish transportation started in 2016 when it decided to rent out a new type of container to improve the efficiency of Japan's live fish business. Based in Tokyo, the company came up with the idea after trial-and-error and a series of experiments.

Known as the Gyokatsu Box (Gyokatsu means live fish in Japanese), the container helps ensure that live fish arrive at their destination in peak condition. With a rental fee between 2500 and 5000 yen per day (between €20 and €40), this ingenious innovation could greatly change transport in Japan's seafood supply chain.

The Gyokatsu box fits neatly on the back of a truck, and is ideal for rail transport. Image: Nikken Lease Kogyo Co., Ltd

With triple layer protection inside, the square container has a 1.93 metre length, with a breadth of 1.07 metres and is 1.09 metres in height, giving it a capacity of 1200 litres of artificial seawater.

A key feature is that fish can be put to sleep through the CO2 method, which temporarily anaesthetises fish for long distance transport. A bubbling device at the container's side releases ultrafine bubbles of dissolved oxygen and CO2, creating a steady flow of water and an even concentration of oxygen in the tank. This suppresses the activity of the fish without killing them. Depending on the species, the fish fall asleep after three to ten minutes.

An oxygen cylinder and liquid CO2 cylinder mounted to the container enable a maximum of 40 hours' endurance. Also on the container is a valve that removes wastewater and waste excreted by the fish, while the number of fish it carries varies depending on type. In the case of red sea bream, up to 300kg, or around 200 fish weighing around 1.5kg, can be transported.

‘The key to the container is the bubbles of oxygen,’ said Mr. Shosuke Watanabe, Nikken Deputy General Manager.
‘Because they are extremely small, they lose their buoyancy and stay in the water. This creates an environment rich in oxygen that the fish can survive in whilst sedated. We are also working with Tokai University's School of Marine Science and Technology to see whether this is impacting fish quality and it seems there are no negative effects.’

The container doesn't require extra time or labour for the transfer of live fish from one truck to another or to a freight container. It can be easily moved with forklift trucks, and because the fish are put to sleep it's possible to prevent any damage that might be caused, for example as they rub against each other during transportation. This maintains their quality and value.

‘There are other things we can do to improve further,’ Shosuke Watanabe said.

‘For example, the containers have a battery that runs for up to 40 hours and they can also be used as storage tanks if plugged into a power supply. We're now investigating alternative power sources and developing new products that will further increase transportation times.’

Rail instead of road

The container is also addressing challenges faced by Japan's fishing industry. Because it can be used on trains, transporting live fish by rail seems to be an answer to the lack of drivers with the necessary skills and capacity to transport live fish. Live fish in Japan can also only be transported by special vehicles in bigger lots of over 10 tonnes, making it difficult for smaller ports with smaller catches. Thanks to the container, however, fish can be delivered in smaller lots.

This has increased incomes, as fishermen in smaller ports are able to use the containers to ship fish across Japan. Another concern for the fishing industry is the decline in fish consumption among Japanese consumers and the high number of people who are unaware of the many delicious fish across the country. Nikken's new container has created a strong network across Japan and allowed people in cities to eat fish that could once only be eaten in certain regions.

The team behind the development of the Gyokatsu containers have been receiving interest from other countries in this method of transportin glive fish. Image: Nikken Lease Kogyo Co., Ltd

Interest from Japan and abroad has been widespread. Following a successful display at the Osaka Seafood Show in February 2019, Shosuke Watanabe is confident in the new container's potential.

‘It was very well received in Osaka,’ he said. ‘The city is home to many fishing industry workers and a strong fish culture. We had detailed business discussions with large firms, including sushi chains, and have had enquiries from one firm that is shipping live fish from Kansai airport to Hong Kong.’

There have been difficulties in developing products that ensure good fish quality, and this has left many in the fishing sector wary of new items, although it is recognised that the fishing industry must be prepared to innovate if it wants to ship its catches further afield. In that sense, the Gyokatsu box will have a key role to play.